UE-70176

Confusing build error message provided when semi-colon is not added after a forward declaration in an Interface header file

Confusing build error message provided when semi-colon is not added after a forward declaration in an Interface header file

Description

If a forward declaration of a class is made in the header file for an Interface class, and no semi-colon is included at the end of the forward declaration line, the build will fail with a confusing error message. The error message says to check that UE4 prerequisites are installed, which has nothing to do with the actual error in this case.

REGRESSION:
No. The same behavior occurs in 4.20.3

Steps to Reproduce

Create a new Basic Code project.

Build the project in Visual Studio.

Open the project in the Editor.

Add a new Unreal Interface class to the project.

In the header file for the new class, add a forward declaration of another class before the UINTERFACE() macro. Make sure no semi-colon is included at the end of the forward declaration.